PANCE Genitourinary Practice Test

Finasteride works by inhibiting the enzyme 5-alpha-reductase, which lowers dihydrotestosterone (DHT) levels. Since DHT drives prostate growth, reducing it causes the prostate to shrink over time, leading to less obstruction and improved urinary symptoms. Other options like alpha-1 blockers relieve symptoms quickly by relaxing smooth muscle in the bladder neck and prostatic urethra, but they do not shrink the gland. Potential side effects include decreased libido, erectile dysfunction, and gynecomastia.